Air break contactors, for example, for controlling three phase electric currents and having a rotatable armature, have previously been operated by an electromagnet coil mounted at the end of the armature. A disadvantage of mounting an operating coil at the end of the armature is that stress is developed within the armature, and the end of the armature distant from the operating coil may twist so as to impair electric contact at the contacts distant from the operating coil.
Longstanding problems in the design of air break contactors have been the tendency of the armature to twist or warp under the influence of an operating coil located at the end of the armature. Also a longstanding problem in the design of an air break contact has been the inconvenient means available for mounting and demounting the arc chutes for the contact.